Cook strawberries, sugar, cornstarch, and lemon juice over medium heat until thickened (5–7 minutes). Cool completely.
Beat cream cheese, sugar, vanilla, flour, and egg yolk until smooth. Chill for 10 minutes.
Cut puff pastry into squares, fill with cheesecake and strawberry mixtures, fold, seal edges with fork.
Brush with egg wash, bake at 400°F (200°C) for 15–18 minutes until golden brown.
Mix powdered sugar, milk, and vanilla; drizzle over cooled turnovers.
